During the production of optoelectronic components such as LEDs, for example, the semiconductor chips are often mounted on leadframes serving for making electrical contact with the optoelectronic component. A housing and/or a lens for the optoelectronic component can be produced by compression molding or injection molding, for example, wherein a plastic such as, for example, a thermoplastic, a thermosetting plastic or an elastomer is applied to at least one side of the leadframe. During the automated manufacture of LEDs, generally a multiplicity of semiconductor chips are simultaneously mounted onto a leadframe comprising a multiplicity of chip mounting areas and are subsequently simultaneously encapsulated with the housing material by molding or injection molding and the leadframe is subsequently singulated by sawing, for example, to form individual optoelectronic components.
Outside the mounting region for the semiconductor chips, the leadframe is generally provided with holes or slots in order, in particular, to reduce mechanical stresses which might otherwise lead to fracture of the assemblage composed of a multiplicity of components. However, there is the risk of plastic material undesirably reaching the rear side of the leadframe through such openings in the leadframe during the compression molding or injection molding of housings and/or lens onto the components.